Zinc phosphate layers are used in the prior art for surface treatment of galvanized fine steel sheet in order to improve surface-relevant properties of the galvanized fine steel sheet. These include, in particular, increasing the corrosion resistance and improving the formability and adhesion of surface coatings.
It has been found by the applicant that, in past years, not periodic, always recurring surface coating adhesion problems occurred on, for example, electrolytically galvanized and phosphated metal strip, in particular steel strip (fine sheet).